In modern computers, large amounts of heat are generated within the central processing units (CPUs) which must be removed in order to maximize speed and reliability, to extend product life, and to prevent spontaneous failure due to overheating. Heat may be removed from CPUs by attaching an air-cooled heat sink or a liquid-cooled cold plate to the top of the processor die, with a thermal interface material (TIM) placed between the chip die and cooling apparatus to reduce the large thermal contact resistance that can occur at bare solid-solid surface contacts. Although the use of TIMs is closely associated with electronics thermal management, TIMs may also be used in other engineering or industrial application for which minimizing the thermal interface resistance between surfaces is desirable.
While some thermal interface materials may be able to reduce the thermal contact resistance as compared to bare surfaces, the thermal resistance of the TIM itself may be a significant contributor to the total thermal resistance between the chip and the cooling environment, thereby limiting the amount of heat which can be effectively removed from the processor while maintaining the temperature within an acceptable range of values. The limit on the amount of heat that can be removed may limit the power and processing capabilities of the CPU. In some cases, grease-like or paste-like TIMs contain volatile compounds which degrade or can be lost after long-term exposure to the elevated temperatures associated with electronics thermal management. Such mass loss and other types of TIM “pump out” may leave air voids between the processor and the cooling apparatus, resulting in the creation of localized regions of elevated temperature on the processor chip which may lead to premature failure.